Synergistic Interface Stabilization and Dynamic Defect Passivation for High‐Performance Ultraviolet‐Stable Perovskite Solar Cells

ABSTRACT

Despite major efficiency breakthroughs in inverted perovskite solar cells (PSCs), their stability under ultraviolet (UV)‐induced degradation remains challenging because photoinduced defect accumulation in the perovskite and deterioration of the buried ITO/SAM/perovskite interface occur simultaneously under illumination. We develop a bulk/interface synergistic stabilization strategy by combining dynamic perovskite defect regulation with buried‐interface reinforcement. The photoisomerizable molecule 1,3,3‐trimethylindolino‐6'‐bromobenzopyrylospiran (TIBBP) serves as a dynamic passivator. It responds to light and reversibly transitions from a closed form to an open form, enabling a continuous functional pathway from film formation to device operation. The closed form regulates crystallization and initial defects, while the UV‐induced open form generates multiple active sites for passivating newly formed defects. To strengthen the buried hole‐transport interface, [4‐(3,6‐difluoro‐9H‐carbazol‐9‐yl)phenyl]phosphonic acid (F‐PhPACZ) is designed as a UV‐durable SAM. The conjugated backbone improves SAM chemical stability and ITO anchoring under UV stress, while fluorine‐related interactions contribute to buried‐interface passivation and improved perovskite growth. By simultaneously suppressing perovskite defect evolution and buried‐interface degradation, the inverted PSC achieves a power conversion efficiency of 27.18% (certified 26.65%) and markedly improved stability under UV irradiation, air exposure, and thermal aging. This work provides a device‐failure‐pathway‐oriented strategy for efficient and stable inverted perovskite photovoltaics.